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Biomedical subjects

F Sztaricskai

Publications and source records attributed to F Sztaricskai.

At least 19 recordsLinked to original sources

Synthesis of new cyclitol compounds that influence the activity of phosphatidylinositol 4-kinase isoform, PI4K230.

The synthesis, chemical derivatization, and investigation of the inhibitory properties of novel cyclitol derivatives on the phosphatidylinositol 4-kinase enzymes PI4K55 and PI4K230 involved in the phosphatidylinositol cycle are reported. Some of the prepared cyclitol derivatives (i.e. 9, 11, 12, and 14) proved to be very powerful and specific irreversible inhibitors of PI4K230 at or below a concentration of 1 mM.

Animals↗

[The fight against bacteria: the antibiotics policy].

Development of bacterial resistance towards antibiotics is no longer a local phenomenon. It has by now become a European and global problem, as a result of unjustified and unprofessional administration of antibiotics in gratuitously high quantities, not only in the medicinal practice, but also in the agriculture. The resistant bacteria may spread from animals to humans, transmitted by the food-chain. A recent danger includes the appearance of the vancomycin-resistant strains (VRSA) besides the methycillin-resistant Staphylococcus aureus (MRSA) infections. The number of the vancomycin-resistant Enterococci (VRE) is also expected to grow in the future. The present paper reports the results of the international activities in the past decades, which is related to the fight against resistant bacteria. Such research involves the production of synthetic compounds, the development of semi-synthetic beta-lactam-, aminocyclitol-, macrolide-, and glycopeptide antibiotics, as well as the introduction of new enzyme-inhibitory substances. Elaboration of basic principles of the rational application of antimicrobial agents is an increasingly urgent need along with the establishment of national and European data bases in which the supply and consumption of related medicines are registered and kept under control.

Amikacin↗

[Synthesis of phosphoramide mustard analogues belonging to the L-sugar series].

During the past decades numerous cyclophoshamide (mustard) derivatives of nucleosides and aminodeoxy sugars have been prepared for investigating their antitumor activities. The cyclophosphamide analogues of aminotrideoxy hexoses belonging to the D-series of sugars have been prepared by Monneret et al. The present paper reports the synthesis of the new phosphoramide mustards 16-17 from 12 and 15 (belonging to the L-sugar series). First compound 10 was synthesized from the L-rhamnose (9). Methyl 3-azido-2,3,6,-trideoxy-alpha-L-ribo-hexopyranoside (11) was obtained by the replacement of the 3-O-p-toluene-sulfonyl group of 10 with sodium azide. Methyl 3-azido-2,3,6,-trideoxy-alpha-L-arabino-hexopyranoside (14) was synthesized by rign opening of 13 with sodium azide. The corresponding amino sugars (12, 15) were obtained by catalytic hydrogenation (over palladium on carbon) of 11 and 14. Our compounds 12 and 15 were transformed into the cyclophosphamide derivatives 16a,b-17a,b upon treatment with bis(2-chloroethyl)phoshoramidic dichloride in the presence of triethylamine (36 h, r.t.). The approximately 1:1 mixtures of isomers (due to the different steric position of the P=O group) could be readily separated by chromatography. The 1H NMR assignments of compounds 16a, 16b, 17a and 17b, were based on one-dimensional selective decoupling experiments or two-dimensional chemical shift-correlated spectroscopy (COSY-60). The assignment of configuration to the isomeric phosphoramidates was based on the magnetic anisotropy of the P=O bond. The distinctly different chemical shift patterns of sugar protons observed for the two isomers allowed the unambiguous assignment of the P=O stereochemistry. The compounds 16a,b-17a,b (mixture of isomers) were tested for inhibitory activity using L1210 and HT29 cell lines.

Antineoplastic Agents, Alkylating↗

Antiulcer effect of the N- and O-beta-D-glucopyranosides of 5-aminosalicylic acid.

Starting from methyl 5-nitrosalicylate (20) the N- and O-beta-glucopyranosyl derivatives (24, 28) of 5-aminosalicylic acid were prepared. The LD50 values of these compounds were determined on mice, and the inhibitory effect of 24 (0.83 mmol/kg) and 28 (1.2 mmol/kg) on gastric ulcer on rats, induced by indomethacin was investigated.

Aminosalicylic Acids↗

Synthesis of phosphoramide mustard analogues of daunomycin and carminomycin.

New phosphoramide mustards (6-8) have been prepared from the antibiotics 2 and 3, and from 5. The mixture of cyclophosphamides could be separated by preparative layer and column chromatography. The assignments of configuration to the isomeric phosphoramidates was based on the magnetic anisotropy of the P = O bond. The synthesized compounds 6a,b-8a,b (mixture of isomers) were tested for inhibitory activity on the [3H]-thymidine incorporation into the DNA of tumor cells, using ovarian carcinoma cell line.

Antineoplastic Agents, Alkylating↗

Chemical synthesis and structural study of lincomycin sulfoxides and a sulfone.

Oxidation of lincomycin with dimethyldioxirane resulted in the sulfoxide-glycosides 3a and 3b, whose treatment with osmium tetraoxide and N-methylmorpholine-N-oxide afforded the same sulfone; 4. According to FAB-MS and CD investigations, the absolute configuration of the sulfur atom in 3a and 3b is R and S, respectively. The new, unsaturated antibiotic analog (6) derived from clindamycin exists in the 4C1 conformation. The antibiotic activities of the synthesized compounds were also studied.

Anti-Bacterial Agents↗

Synthesis of new pseudodisaccharide aminoglycoside antibiotics from carbohydrates.

Novel pseudodisaccharide-type aminocyclitol antibiotic models, built up from D-arabinose, D-ribose, D-glucosamine, L-ristosamine and L-acosamine have been synthesized by the glycosylation of suitably protected (azido)deoxyinosose aglycones derived by the Ferrier carbocyclic ring transformation of carbohydrate precursors. An alternative approach to related pseudodisaccharides, based on the Ferrier carbocyclization of reducing disaccharides, has also been elaborated. This latter method extends the scope of the Ferrier reaction, by demonstrating that acid-labile 2-deoxydisaccharides can also be readily transformed into the corresponding pseudodisaccharides under the slightly acidic conditions of this ring-transformation.

Aminoglycosides↗

Synthesis of a phenyl beta-avobioside derivative of the disaccharide component of avoparcins.

The synthesis of the phenyl beta-glycoside of avobiose, a disaccharide fragment present in the antibiotic avoparcin, is reported. It is based on glycosylation of phenyl 3,4,6-tri-O-benzyl-beta-D-glucopyranoside with 2,3,6-trideoxy-4-O-p-nitrobenzoyl-3-trifluoroacetamido-L-ribo-hex- 1-enitol, a fully protected glycal of L-ristosamine, in the presence of trimethylsilyl triflate.

Anti-Bacterial Agents↗

A new cyclitol derivative influences inositol metabolism in Neurospora crassa.

Cyclitol derivatives have been synthesized and screened for growth inhibitory effect upon prokaryotic and eukaryotic organisms. One derivative, (2S,3R,5R)-3-azido-2-benzoyloxy-5-hydroxycyclohexanone, was studied in detail: it has no effect upon bacteria, but it is inhibitory to Neurospora crassa. In Neurospora crassa it increased the amount of myo-inositol-1-phosphate synthase and inhibited the activity of myo-inositol-monophosphatase. The enhanced synthesis of myo-inositol-1-phosphate synthase was the consequence of lowering the intracellular inositol concentration. Li+ treatment of Neurospora crassa has effects similar to those of P.I.-658.

Cell Division↗

An NMR study of eremomycin and its derivatives. Full 1H and 13C assignment, motional behavior, dimerization and complexation with Ac-D-Ala-D-Ala.

Complete 1H and 13C NMR assignments are presented for eremomycin (1) and some of its desglycosylated derivatives 2, 3 and compared to the structurally closely related glycopeptide vancomycin. Primary structure and stereochemistry of eremomycin is corroborated by the present high field total correlation spectroscopy, NOESY and heteronuclear multiple-bond correlation NMR methods. A rough motional characterization of the title compound is attempted by 13C-T1 and 13C-[1H] NOE measurements. Dimerization of eremomycin is observed both in DMSO-d6-CCl4 and D2O solutions. Complexation with cell wall analogue dipeptide Ac-D-Ala-D-Ala is also demonstrated.

Anti-Bacterial Agents↗